JP2009123516A - Sealing method of metal container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing method capable of achieving high pressure resistance by sandwiching insulating resin between a metal container and an upper lid, and thermally fusing the insulating resin to seal. <P>SOLUTION: A gasket 4 is irradiated with a laser beam 14. An upper lid connection plate 5 is irradiated with the laser beam 14 transmitting the gasket 4 by irradiating with the laser beam 14, and the upper lid connection plate 5 is heated. The gasket 4 closely attached to the upper lid connection plate 5 is fused by heat conduction and is fuse-bonded. A flat part 6 of a width of 2 mm is provided on the upper lid connection plate 5, and the laser beam is irradiated to the flat part 6. Although the upper lid connection plate 5 is likely to have a curved surface because its outer circumference is folded, the flat part is purposefully provided to suppress fluctuation of an absorption rate of the laser beam upon irradiating the laser beam on the flat part. Thus, bonding quality can be stabilized irrespective of fluctuation factors such as irradiation target miss. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealing method in which a metal upper lid is inserted into an opening of a metal container and sealed by caulking.

  A method is known in which an insulating resin is sandwiched between a metal container and a metal upper lid and the container and the upper lid are sealed by heat-sealing the resin.

  For example, Patent Document 1 discloses a method of sealing a container and an upper lid by heating the container and the upper lid with a heating and pressing jig to melt an insulating resin therebetween.

  Patent Document 2 discloses a method of sealing an container and an upper lid by melting an insulating resin with a high-frequency heating device.

JP-A-3-01440 JP 7-73861 A

  In the conventional technology, the strength of the sealing portion is proportional to the strength of the insulating resin, but the strength of the insulating resin tends to be lower than that of the metal. In order to improve the reliability of sealing, it is necessary to improve pressure resistance.

  Further, in the conventional technology, when the insulating resin is melted, the insulating resin is melted by a heating / pressing jig or high-frequency heating, so that the temperature of the container rises.

  For example, in the case of a container for a battery such as a lithium secondary battery, the temperature of the electrolytic solution may increase and the battery characteristics may deteriorate.

  Accordingly, an object of the present invention is to provide a sealing method in which an insulating resin is sandwiched between a metal container and a metal top lid and the pressure resistance is not reduced when the insulating resin is sealed by thermal fusion. There is.

  In the sealing method of the present invention, a metal top lid is inserted into the opening of the metal container, and a peripheral edge of the opening of the metal container is passed through an insulating gasket made of a thermoplastic resin that transmits laser light. After the caulking process is performed on the metal container, the caulking process part and the insulating gasket that have been caulked are irradiated with laser light.

  It is preferable to provide a flat portion in the caulking portion, irradiate the flat portion with laser light, and irradiate the insulating gasket in contact with the flat portion of the metal upper lid with laser light.

  Then, it is preferable that the insulating gasket in contact with the caulking portion is heated and melted by heat conduction by laser beam irradiation to the caulking portion, and a part thereof is decomposed and vaporized.

  Then, the laser beam that has passed through the insulating gasket by the irradiation of the insulating gasket with the laser beam is absorbed by the metal upper lid, the metal upper lid is heated, and the insulating gasket that is in contact with the metal upper lid is thermally conductive. It is preferable to melt by heating and to partially decompose and vaporize.

  Further, the sealing method of the present invention is a metal container having a metal upper lid inserted into the opening of the metal container, with an insulating gasket made of a thermoplastic resin around the periphery of the opening of the metal container. After the caulking process, the caulking process part that has been caulked and the metal upper lid are irradiated with laser light.

  Then, it is preferable to provide a flat portion in the caulking portion, irradiate the flat portion with laser light, and provide a flat portion on the metal upper lid, and irradiate the flat portion with laser light.

  Then, it is preferable to heat the insulating gasket that is in contact with the caulking portion by heat conduction by heating the caulking portion with laser light irradiation, and to thermally vaporize and decompose a part thereof.

  Then, by irradiating the metal upper lid with laser light, the metal upper lid is heated, and by heat conduction, the insulating gasket in contact with the metal upper lid is heated and melted, and a part thereof is decomposed and vaporized. preferable.

  Further, the sealing method of the present invention is a method in which a metal container is caulked through an insulating rubber on the peripheral edge of the opening of the metal container with a metal upper lid inserted in the opening of the metal container. After that, the caulking portion and the metal upper lid that have been caulked are irradiated with laser light.

  As described above, in the present invention, a container is caulked through an insulating gasket made of a thermoplastic resin that transmits laser light at the peripheral edge of the opening of the container with the metal upper lid inserted into the opening of the metal container. . Thereafter, the caulking portion and the gasket are irradiated with laser light, the laser light transmitted through the gasket is irradiated onto the upper lid, and the upper lid is heated to heat and melt the gasket in contact therewith.

  Thereby, the container and the gasket, and the upper lid and the gasket can be welded and sealed, respectively.

  In this method, the pressure resistance of sealing is ensured by caulking, and local heating is possible with laser light, and sealing can be performed without increasing the temperature inside the container.

  Further, by providing a flat portion in the caulking portion, irradiating the flat portion with laser light, and also providing a flat portion on the upper lid and irradiating the flat portion with laser light, the laser light absorption rate Therefore, stable sealing is possible.

  In addition, since the container or the upper lid has a surface roughness, even if the gasket is pressed and compressed by caulking, there is a gap between the container and the gasket, or between the upper lid and the gasket, although it is less than the surface roughness. Arise.

  On the other hand, the gasket is heated and melted, and further heated to a temperature at which a part is decomposed and vaporized, so that the volume of the resin expands and the pressure of the molten resin increases, and the air in the gap is discharged. Therefore, welding without gaps is possible.

  In addition, after the metal upper lid is inserted into the opening of the metal container, the container is caulked to the peripheral edge of the opening of the metal container via an insulating gasket made of thermoplastic resin, and the caulking portion and Welding is also possible by irradiating the upper lid with laser light.

  The container-gasket welding mechanism is as described above.

  Welding of the upper lid and the gasket can be achieved by irradiating the upper lid with laser light to heat the upper lid and heat and melt the gasket in contact with the upper lid by heat conduction. In this case, the gasket can be fused even with a resin that does not transmit laser light.

  Further, the gasket material can be the same effect even if it is not thermoplastic resin but silicone rubber or the like.

  The effect of the present invention is to provide a sealing method in which an insulating resin is sandwiched between a metal container and a metal top lid and the pressure resistance is not reduced when the insulating resin is sealed by thermal fusion. it can.

  Hereinafter, examples will be described with reference to the drawings.

  The first embodiment will be described with reference to FIGS.

  FIG. 2 shows a cross-sectional view of the battery.

  The upper lid connecting plate 5 is integrated by bending the outer periphery of the upper lid cap 7, and these are sealed by caulking with the groove 2 and the bent portion 3 via the gasket 4.

  In addition, a positive electrode plate 11 and a negative electrode plate 12 are wound inside the container 1 via a separator 10. The negative electrode plate 12 is connected to the container 1 via the negative electrode current collector plate 13.

  On the other hand, the positive electrode plate 11 is connected to the upper lid connection plate 5 via the positive electrode current collector plate 9 and the leads 8. An electrolytic solution is injected into the container 1.

  The container 1 is made of stainless steel having a thickness of 0.5 mm, the upper lid connecting plate 5 is made of aluminum having a thickness of 0.5 mm, and the upper lid cap is made of stainless steel having a thickness of 0.5 mm.

  These materials can also be Ni-plated carbon steel.

  The gasket 4 is made of polypropylene, which is a thermoplastic resin, and has a thickness of 1.0 mm. The material of the gasket 4 is a thermoplastic resin for fusing, and is also required to be elastic because it is caulked.

  Further, as will be described later, transparent polyethylene is used for the gasket 4 because the laser beam 14 needs to be made of a transparent material.

  FIG. 1 shows a cross-sectional view of the state of laser light irradiation on the gasket.

  The gasket 4 was irradiated with a laser beam 14. The laser beam 14 uses a YAG laser and is irradiated at an output of 1 kW and a laser heating moving speed of 1 m / min, so that the laser beam 14 transmitted through the gasket 4 is irradiated to the upper lid connecting plate 5 and heats the upper lid connecting plate 5. . The gasket 4 in close contact with the upper lid connecting plate 5 is melted and fused by its heat conduction.

  The same effect can be obtained even if the laser beam 14 is a semiconductor laser or a carbon dioxide gas laser.

  The upper lid connecting plate 5 is provided with a flat portion 6 having a width of 2 mm, and the flat portion 6 was irradiated with laser light.

  The upper lid connecting plate 5 tends to be curved because the outer periphery is bent, but it is possible to suppress fluctuations in the absorption rate of the laser light by providing a flat portion and irradiating it. That is, it is possible to stabilize the welding quality against any fluctuation factors such as the irradiation target.

  FIG. 3 shows a cross-sectional view of the irradiation state of the laser beam to the bent portion.

  The bending portion 3 is irradiated with a laser beam 14. As a result, the bent portion 3 is heated, and the adhered gasket is melted and fused by the heat conduction. Irradiation is performed using a YAG laser with an output of 1.2 kW and a laser heating moving speed of 1 m / min.

  FIG. 4 shows a cross-sectional view of the laser irradiation part.

  An outer melt-solidified region 15 is formed in the gasket 4 in contact with the flat portion 6, and bubbles 16 are formed therein. Further, the inner melt-solidified region 17 and the bubbles 16 are also formed in the gasket 4 in contact with the bent portion 3.

  The flat portion 6 and the bent portion 3 have a surface roughness of about several μm. Therefore, even if the gasket 4 is pressed and compressed by caulking, a gap is generated between the flat portion 6 and the gasket 4 or between the bent portion 3 and the gasket 4 although it is less than the surface roughness.

  On the other hand, the gasket 4 is heated and melted, and further heated to a temperature at which a part of the gasket 4 is decomposed and vaporized, whereby the volume of the molten resin is increased and the pressure of the molten resin is increased. Since welding can be performed while discharging, welding without gaps becomes possible. If there is a gap, the internal electrolyte leaks little by little in the long run, which is also effective in preventing this leakage.

  As described above, since the local heating is performed by the laser beam 14, the gasket 4 can be fused without increasing the temperature of the electrolytic solution.

  Further, since it is caulked, sealing with high pressure resistance is possible.

  Moreover, since both surfaces of the gasket 4 are fused, it is possible to perform a good sealing without any leakage.

  Further, the gasket can be made of the same effect even if it is not thermoplastic resin but silicone rubber or the like.

  Further, in this embodiment, the sealing of the cylindrical battery container is described, but the same effect can be obtained for a square battery.

  In addition to this, it is possible to provide a method for sealing the insulating resin by heat welding without increasing the temperature of the substance inside the container.

  A second embodiment will be described with reference to FIGS.

  This embodiment is different from the first embodiment in that black gasket that does not transmit laser light 14 is used for the gasket 4.

  FIG. 5 shows a cross-sectional view of the state of laser light irradiation on the flat portion in the second embodiment.

  Since the gasket 4 does not transmit the laser beam 14, the flat portion 6 is irradiated with the laser beam 14 to heat the flat portion 6 and melt and fuse the gasket 4 in contact with the flat portion 6 by the heat conduction. To do.

  FIG. 6 shows a cross-sectional view of the state of laser light irradiation to the bent portion in the second embodiment.

  FIG. 6 is the same as FIG. 3 of the first embodiment.

  FIG. 7 shows a cross-sectional view of the laser irradiation part in the second embodiment.

  The difference from the first embodiment is that the gasket 4 is melted by heat conduction because the flat portion 6 is irradiated with the laser beam 14. In the case of the material of the gasket 4 that does not transmit the laser beam 14, this embodiment is used instead of the first embodiment. According to this embodiment, the same effect as that of the first embodiment can be obtained.

  FIG. 8 shows a cross-sectional view of the state of laser light irradiation in the third embodiment.

  The difference from the first embodiment is to change the focal position of the laser beam 14 to increase the irradiation beam diameter and to irradiate the bent portion 3 and the gasket 4 simultaneously. According to this embodiment, the same effect as that of the first embodiment can be obtained.

  FIG. 9 shows a cross-sectional view of the state of laser light irradiation in the fourth embodiment.

  The difference from the third embodiment is that the upper lid connecting plate 5 is eliminated and the upper lid cap 7 and the gasket are welded. According to this embodiment, the same effect as that of the first embodiment can be obtained.

  In any of the above embodiments, the sealing method can be performed without lowering the pressure resistance, and the insulating resin can be sealed by thermal welding without increasing the temperature of the substance inside the container.

  INDUSTRIAL APPLICABILITY The present invention can be used for a battery in which an electrolytic solution such as a lithium secondary battery is sealed by inserting a metal upper lid into an opening of a metal container and sealing it by caulking.

Sectional drawing of the irradiation condition of the laser beam to a gasket is shown. A cross-sectional view of the battery is shown. Sectional drawing of the irradiation condition of the laser beam to a bending part is shown. Sectional drawing of a laser irradiation part is shown. Sectional drawing of the irradiation condition of the laser beam to the flat part in a 2nd Example is shown. Sectional drawing of the irradiation condition of the laser beam to the bending part in a 2nd Example is shown. Sectional drawing of the laser irradiation part in a 2nd Example is shown. Sectional drawing of the irradiation condition of the laser beam in a 3rd Example is shown. Sectional drawing of the irradiation condition of the laser beam in a 4th Example is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Grooving 3 Bending part 4 Gasket 5 Upper lid connection plate 6 Flat part 7 Upper lid cap 8 Lead 9 Positive electrode current collecting plate 10 Separator 11 Positive electrode plate 12 Negative electrode plate 13 Negative electrode current collecting plate 14 Laser beam 15 Outer melt solidification region 16 Bubble 17 Inner melt solidification area

Claims (9)

  With the metal top lid inserted into the opening of the metal container, the metal container is caulked to the peripheral edge of the opening of the metal container via a thermoplastic resin insulating gasket that transmits laser light. After processing, the sealing method characterized by irradiating the said crimping process part which carried out the crimping process, and the said insulation gasket with a laser beam.   The flat portion is provided in the caulking portion, the laser beam is irradiated to the flat portion, and the insulating gasket in contact with the flat portion of the metal upper lid is irradiated with the laser beam. Sealing method.   The heat treatment is performed by irradiating the caulking portion with laser light, the insulating gasket in contact with the caulking portion is heated and melted by heat conduction, and a part thereof is decomposed and vaporized. Item 2. The sealing method according to Item 1.   The laser beam transmitted through the insulating gasket by the irradiation of the insulating gasket with the laser beam is absorbed by the metallic upper lid, and the metallic upper lid is heated to come into contact with the metallic upper lid by heat conduction. The sealing method according to claim 1, wherein the insulating gasket is heated to melt and a part thereof is decomposed and vaporized.   After the metal container is caulked to the peripheral edge of the opening of the metal container via an insulating gasket made of thermoplastic resin, with the metal upper lid inserted into the opening of the metal container, A sealing method comprising irradiating a laser beam to a caulked portion that has been caulked and the metal upper lid.   6. A flat part is provided in the caulking part, a laser beam is irradiated on the flat part, a flat part is provided on the metal upper lid, and the flat part is also irradiated with a laser beam. The sealing method as described.   The heating is performed by irradiating the caulking portion with laser light, the insulating gasket in contact with the caulking portion is heated and melted by heat conduction, and a part thereof is vaporized and decomposed. Item 6. The sealing method according to Item 5.   By irradiating the metal top lid with laser light, the metal top lid is heated, and by heat conduction, the insulating gasket in contact with the metal top lid is heated and melted, and a part thereof is decomposed and vaporized. The sealing method according to claim 5.   With the metal top lid inserted into the opening of the metal container, the metal container is caulked to the periphery of the opening of the metal container via an insulating rubber, and then the caulking is performed. A sealing method comprising irradiating a laser beam onto a processing portion and the metal upper lid.

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